The invention relates to fluid filters for filtering fluid from a machine, including spin-on type oil filters for internal combustion engines and hydraulic equipment, and more particularly to an in-situ cleanable filter facilitating modularity meeting evolving market demands.
The present invention arose during further development efforts relating to the subject matter of commonly owned U.S. Pat. Nos. 5,462,679, 5,779,900, 5,858,224, and allowed U.S. application Ser. No. 08/755,479, filed Nov. 22, 1996, all incorporated herein by reference. Such subject matter generally relates to cleanable filters, including oil filters, and more particularly to the use of a cleaning fluid, such as pressurized air, to clean the filter at a convenient site relative to the installation of the filter on a machine such as an internal combustion engine.
In prior art cleanable oil filters, it is typical that the oil inlet and outlet are separated from the oil drain and air inlet. The oil inlet and outlet are typically at the top of the filter housing, while the oil drain and air inlet are at the bottom of the filter housing. Separation of the oil inlet and drain reduces potential contamination of upstream oil flow lines by backflushed contaminant. The bottom air inlet ensures that air bubbled through the oil creates a foam prior to reaching the filter media.
Separation of the oil inlet, oil outlet, oil drain and air inlet may not be conducive to certain evolving modular designs using a permanent assembly intended to be part of the engine or equipment. In such modular designs, it is desired that the filter assembly include not only a cleanable and replaceable cartridge filter element, but also associated plumbing. Modular designs bolted onto the engine or equipment are becoming increasingly popular. The present invention addresses and solves this need in a particularly simple and efficient manner.